The first thing we did when the news came in that the capital of Afghanistan had fallen to our enemies was reach for our dog-eared copy of Peter Kann’s “Obituary for South Vietnam.” It was issued in the Wall Street Journal on May 2, 1975, the morrow of the communist conquest. We later personally heard the Journal’s legendary editor, Robert Bartley, call it the finest op-ed piece he’d ever published.

What distinguished it from the cataract gushing from the editorial pages of the day was a sympathy for our defeated allies, a fidelity to the ideals for which our GIs went to war, and a visceral distaste for the totalitarianism that drove the Soviet Union and its puppets in Hanoi to victory. He acknowledged that there were many Americans who “breathed a sigh of relief” when Vietnam fell, but he was with the mourners.

That is where our own sentiments lie today in respect of Afghanistan. They lie with the GIs who gave their hearts — and all too often their lives — to a fight that was launched against our country, out of the blue, by al Qaeda and their Taliban hosts in Afghanistan. They lie with the Afghan soldiers, warlords, and leaders who sided with America. And the millions of Afghan women and men who dreamed of an end of oppression.

To hear an American president talk as Mr. Biden does about a war-time ally is shocking. Mr. Biden has tried to palm off on his countrymen the idea that he was bound by an agreement President Trump made for a May deadline. Mr. Biden has made it his business to tear up every commitment Mr. Trump made on anything. That Mr. Biden couldn’t find it within himself to break with Mr. Trump on Afghanistan reeks of hypocrisy.

What a contrast to the way our presidents conducted themselves during Vietnam. When our Free Vietnamese allies had their backs to the wall, President Nixon and then President Ford pleaded with Congress to help Vietnam stay in the fight. Henry Kissinger literally prowled the halls of Congress. In contrast, when Afghanistan had its back to the wall against the Taliban blitzkrieg, Mr. Biden and his aides have resorted to blame-shifting the consequences of his actions.

There has been no talk of the strategic importance of Afghanistan and our bases there, though it is well understood by our military leaders (and GIs). Iran lies to the West, Pakistan to the South, China to the East. Afghanistan has long been known as the Asian roundabout. Without a presence there, we lose all access to Central Asia. Mr. Biden might come to miss that feature of the Afghan drama soon enough.

The communist camarilla in China certainly wasted no time in recognizing the Taliban as the rulers of Afghanistan. They were the first to do so. Afghanistan can be expected to emerge as a communist Chinese client. Mr Biden shows no remorse. The Chinese see the strategic value he fails to grasp. Giving up Afghanistan was not only a moral mistake, a betrayal, it was also a strategic mistake.

The saddest part of the obituary of Afghanistan is that it didn’t have to be this way. We could have ended the war and maintained a few thousand troops there on a couple of bases. That is what we’ve typically done following a war — think Japan, Germany, Italy, and South Korea. We have troops stationed in all these countries, in addition to more than a hundred others, and indefinitely.

At the end of his “Obituary for South Vietnam,” Mr. Kann, one of the conflict’s great reporters and the son of a world-scale historian (of the Habsburg Empire), noted that history was unlikely to look kindly on the defeated country. He himself, though, preferred the imperfect South Vietnam to the communist zealots of the north, just as we prefer our imperfect Afghan allies to the Taliban. Mr. Kann noted that he wasn’t writing history, though, just an obituary for the country he’d covered.